type goal = int
type status = proof * goal
+ (** @param goal
+ * @param goal's metasenv
+ * @return initial proof status for the given goal *)
+val initial_status: Cic.term -> Cic.metasenv -> status
+
(**
a tactic: make a transition from one status to another one or, usually,
raise a "Fail" (@see Fail) exception in case of failure